Brazil to Sterilize Zika Mosquitoes with Radiation

MARVIN RECINOS/AFP/Getty Images24 Feb 2016

Brazil has reportedly decided to use the radioactive sterilization of mosquitoes as a means of fighting the Zika virus, with the blessing of the International Atomic Energy Agency, which is shipping the necessary irradiator device.

Dr. Kostas Bourtzis, a molecular biologist working with the IAEA, told Reuters that “a Brazilian non-profit organisation called Moscamed will breed up to 12 million male mosquitoes a week and then sterilize them with the cobalt-60 irradiator, produced by Canadian company MDS Nordion.”

The plan is to release these sterilized males into targeted mosquito breeding areas, resulting in a large number of dud eggs that will cut sharply into the population of the next mosquito generation. The Aedes aegypti mosquitoes that spread Zika have a lifespan measured in weeks, so constant frenzied breeding is necessary to sustain their population. Females drop up to 200 eggs at a time, so each sterilized male should be able to sabotage a large number of eggs.

Brazil is scrambling to get Zika under control before the Summer Olympics in August, which is a very short timetable for the sterilization strategy. Dr. Bourtzis said the program will begin with test runs in a dozen towns in northeastern Brazil, then ramp up for deployment around major cities, if the government chooses to provide the funding.

The effectiveness of radioactive sterilization for controlling the Zika mosquitoes remains to be seen, although Popular Sciencereports the Portuguese have used the technique to control fruit flies on the island of Madeira, as well as “other agricultural insect pests like screw worms and moths.”

Popular Science describes the first stage of Brazil’s sterilization plan as producing about 12 million sterile male mosquitoes per week.

A similar strategy involving genetically-modified “self-limiting” mosquitoes which produce fatally compromised offspring was tested in Brazil last month, in what the UK Telegraph described as a successful trial that reduced wild mosquito larvae by 82 percent, but there is no mention of pursuing this technique in this week’s reports about Brazil exploring radioactive sterilization.

A rash of stories in late January suggested that genetically modified mosquitoes might have causedthe Zika outbreak, but Discoverdenounced this as a “ridiculous rumor” and “random nonsense,” based largely on the unfounded musings of a single Reddit poster.